File transmission services in an existing mobile communication system include a Multimedia Message Service (MMS) which has a limited file size of 500 kB and uses the technology of General Packet Radio Service (GPRS) for transmission at a low transmission rate (maximum 384 kbps, typically 50 kbps) and at a high expense. Although it has relatively fast message delivery time, due to its size limit and high price, this service has never entered to the pervasive mass market. And after receiver retrieves the MMS message, it is immediately deleted from MMS server, and thus can not be reused or shared.
On the trend of the web market, Google and Microsoft have already offered non-deleting search-enabled GB-size email service and file sharing service. However these web-based solutions also have shortcomings of being not aware of the sender and receiver's location information, sender and receiver's web-surfing habit, and being not able to provide better QoS and ubiquitous wireless access. An end user still has to be always online and with a fixed IP, otherwise the TCP connection will break due to a handover across cells and other reasons while a large file is being transmitted with a limited bandwidth. Then the amount of consumed power of the wireless user equipment being online all the time may be dramatically increased. A request to resume the transmission connection directly is currently absent in the HTTP and FTP protocols, and in order to resume a broken transfer, the size of the file transmitted between the client and the server has to be known and a download offset has to be altered correspondingly, which may not be supported by all the servers. An upper firewall within a network path also tends to block the new request to resume the broken transfer because the user equipment may possibly have altered its source IP address. A file-level check is absent in the HTTP and FTP protocols, and an error may occur easily, which case will be worse for a single file being too large. The entire file will also become useless even if a byte in the file is corrupted and has to be downloaded again from the very beginning. Thus it's very difficult to transmit and resume an original file accurately from a remote site via the HTTP and the FTP in a wireless context. Moreover in the Internet-based solutions, an operator becomes a conduit over which data is transmitted but can not control the direct billing information of a subscriber and thus can not easily charge the sender differently.
In view of the foregoing shortcomings in the prior art, it is currently desired to offer a high-speed file transmission, storage and search service in a wireless communication network.